1. Field of the Invention
Contrast media are widely used in x-ray examination. A substantial proportion of the contrast media employed is water soluble polyiodinated aromatic compounds having a variety of water soluble annular substituents. A significant portion of the population has an adverse reaction to the x-ray contrast material. Testing, when done, has been accomplished by subjecting the patient to a small intravascular injection of the contrast medium, but the discriminate potential of this test is low and some patients succumb to the test dose itself.
It would therefore be desirable to have a simple rapid test for screening patients to whom x-ray contrast media will be administered.
2. Description of the Prior Art
Kluft, J. Lab. and Clin. Med. (1978), 91:83-95 discloses an assay for prekallikrein, disclosing a number of activators including dextran sulfate, and employing a chromogenic substrate. Stormorken et al., Haemostasis (1978) 7:69-75 discloses alternative techniques for assaying prekallikrein.
Promoters for prekallikrein are also described in Gjonnaess, Haemorrn 28:182-193, 1972; and Griffin and Cochrane, Seminars in Thrombosis and Hemostasis, 5:54-273, 1979.